Electric conductor



(No Model.)

H. B. COBB. ELECTRIC CONDUCTOR.

No. 429,304. Patented'June a, 1890.

W/TNESSES: m VENTOI? 7% 5 f as, zi xgm fl dww ATTORNEYS.

UNITED STATES PATENT OFFICE, A

HENRY B. COBB, OF XVILMINGTON, DELAWARE, ASSIGNOR TO THE COBB VULCANITE WIRE COMPANY, OF DELAWARE.

ELECTRIC CONDUCTOR.

SPECTFICATION forming part of Letters Patent No. 429,304, dated June 3, 1890.

Application filed November 8, 1889. Serial No. 329,616. (No model.)

To all whom it may concern:

Be it known that I, HENRY B. COBB, a citizen of theUnited States, residing at VVilmington, in the county of New Castle and State of Delaware, have invented anew and useful Improvement in Electric Conductors, of which the following is a specification.

My invention relates to an improvement in the class of conductors used for electric underground systems; and it relates particularly to the construction of conductors involving a metallic wire or number of such wires insulated by being inclosed in tubing of insulating material, such as hard rubber.

Conductors of the class stated are commonly referred to as wires, the term wire being employed generically, as including any metallic wire, number of such wires, or cable inclosed in insulating material, and it is in this sense that the term is employed in the following description.

The objects of my invention are to provide a construction of the wire which'shall afford an exceptionally high degree of insulation; to permit as high (or even much higher) voltage to be used on the circuit as may ever be required and without injury to the wire; to provide against possible flaws in the insulation, and to enable the employment of a considerable thickness of the insulating-tubing without thereby impairing the desired degree of flexibility of the wire.

To these ends my invention consists in the general construction of my improved wire, and it also consists in details of construction and combinations of parts.

In the accompanying drawings, Figure l is a view in perspective of a length of my improved wire, and Fig. 2 is an end view thereof.

A is the m etallic conductor, shown as formed of a number of strands twisted together.

B denotes insulating material immediately inclosing the metallic conductor, and which I prefer to provide in the form of y rubber tubing suflicient-ly hard to resist impression by the weight of the conductor A, though it-may comprise any other insulating substance possessing the desired quality stated.

D D are strands of cord (as cotton) twisted spirally in regular series around the insulation B and embedded in insulating material C of a kind which I term soft insulation, meaning thereby any insulating substance that maybe reduced to aplastic or fluid condition-such as paraffineand which hardens or becomes sufficiently tenacious by exposure to resist attenuation or impression by the weight of the material inclosed within it.

E is the external insulation, in the form of a tube (preferably hard rubber) sufficiently hard to resist abrasion in the manipulation of the wire, such as the drawing in and out of conduits.

To manufacture my improved wire I proceed as follows: The conductor A,inclosed in its insulating material B, is first wound with the cord D, which should be preparatorily soaked in an insulating compound orsubstance, such as paraffine. The outside insulation E is then applied, preferably, in the form of the rubber tubing referred to, through which the combined elements A, B, and D are drawn, the spirally-wound cord D serving to center them inside the tubing, and thus permit the application of the soft insulation C in an equal or substantially equal thickness throughout its entire extent, and which I apply by forcing paraffine, reduced to a liquid condition, through the length to be treated between the insulating parts B and E, the paraifine thus embedding the cord.

Among the particular advantages of the wire of my improved construct-ion are that it affords extraordinarily high insulation; that as the insulating medium is formed in separate layers or thicknesses the joints in the several thicknesses of the parts B and E 1nay,in

producing desired lengths of the wire, be formed out of coincidence with each other, thereby reducing the possibilityof leakage at the joints; that the requisite flexibility of the wire is not prevented by the comparatively great thickness of insulation employed,which, if entirely of hard rubber,would be undesirably stiif, and that any flaws that may exist in the parts B, C,and E are not liable to coineide, thereby affording a practically flawless insulating-covering for the conductor A.

A very good conductor is afforded without the paraffine or anyinsulation other than air and the cord D between the tubes B and E, and I desire to include such construction as within my invention.

lVhat I claim as new, and desire to secure by Letters Patent,.is

1. An electric conductor comprising, in combination,wire A, inclosed in an insulating substance B, the whole being inclosed in a tube E of hard insulating substance, such as vulcanized rubber, and soft insulating material C, such as wax, interposed between the insulations B and E, substantially as described.

2. A11 electric conductor comprising, in combination, wire A, inclosed in an insulating substance B, wound with cord D, the whole being inclosed in a tubing E of hard insulating substance, and soft insulating material C, such as wax, interposed between the insulations B and E and embedding the cord, substantially as described.

3. In an electric conductor, an insulator for the wire, comprising, in combination, a tube B, of insulating materiahhaying a bore adapted to receive the conductor, a tube E, of hard insulating material, having a bore of greater diameter than the tube B and inclosing the latter, and an interposed filling between the tubes, composed of a soft insulating substance, substantially as described.

4. An electric conductor comprising, in combination, wire A, inclosed in hard insulatingtubing B, wound spirally with cord D, a tube E, of hard insulating material, such as vulcanized rubber, inclosing the spirally-wound tube B, and soft insulating material C, such as wax, interposed between the tubes B and E and embedding the said cord, substantially as described.

5. An electric conductor comprising, in combination, wire A, inclosed in hard-rubber tubing B, wound with parafline-soaked cord D, a tube E, of hard rubber,inclosing the spirallywound tube B, and paral'fine C, interposed between the tubes B and E and embedding the said cord, substantially as described.

(3. An electric conductor comprising, in combination,wire A, inclosed in hard-rubber tubing B,wound spirallywith cord D,and inclosed in hard-rubber tubing E, substantially as described,

In witness whereof I have hereunto subscribed my name in the presence of two witnesses.

HENRY B. COBB.

Witnesses:

DOUGLAS DYRENFORTI-l, BRUCE S. ELLIOTT. 

